Abstract: The subject of this research is the role and importance of the critical reasoning and critical rationalism within the system of philosophical views of Lavrov, as well as the significance of critical rationalism for the development of Russian civil society in the second half of the XIX century. The authors examine Lavrov’s solution to the issue of historical emergence and development of the critical thought. The emphasis is made on the importance of critical thought in the historical process. The article also analyzes the anthropological substantiation of critical reasoning; the critical thought of Lavrov is the result of the highest need – a demand for development, which is being interpreted as the ethic need for self-improvement, the need to create new social forms. In the course of this research, the authors reveal the significance of critical thought as a factor which makes crucial changes in personality, society, and public relations. The scientific novelty consists in the interpretation of Lavrov’s position within the framework of the Russian public thought of the second half of the XIX century, not as a revolutionist-democrat, but as an “enlightener”-liberal. Lavrov believed that the social system could be established basing on the enlightenment, on the development of critical thinking via converting the majority of members of the society into the critically thinking people. In the conclusion, the authors note that Lavrov was historically correct.